First, preheat oven to 350ºF and spray an 8×8-inch pan with coconut oil cooking spray and set aside.
Next, mix all crust/crumble ingredients together in a medium/large mixing bowl.
Then, take 2/3 of the mixture and press it evenly onto the bottom of the oiled 8×8 pan. Set the rest of the crust/crumble mixture aside (this is what you will use for the crumble topping).
Bake crust at 350ºF for 10 minutes. Remove crust and set aside.
Next, place all ingredients for the berry filling into a medium sauce pan. Turn heat to high and bring filling to a boil, stirring often and breaking up the blueberries. Once boiling, turn heat down to low and let simmer for 10-15 minutes. Continue stirring.
Once the berry filling has thickened, pour on top of the crust. Spread the rest of the crumble mixture over the top of the berry filling and then bake for another 10 minutes at 350ºF.
Let cool for 20 minutes before placing into the fridge for at least 2 hours to let the filling set. Slice and enjoy!